Transphasic nebula was a type of nebula which had unique transphasic qualities which created minor disturbances in subspace. In 2377, the Borg Collective managed to create a transwarp gate between a transphasic nebula in the Delta Quadrant and a similar nebula in the Regula Badlands region of the Beta Quadrant. The creation of these corridors allowed the Borg to attack and assimilate several Federation and Romulan colonies without encountering significant resistance.